From the Magazine

Even for Slide-Prone Region, Landslide Was Off the Chart

The rugged terrain inland of Seattle is prone to landslides. Yet the latest Oso landslide, which killed at least 27 people on 22 March, stands out as an anomaly. Calculations suggest that it flowed three times farther than slides of similar size and elevation drop, most likely due to the effect of heavy rains on the region's glacier-deposited soils.